1. Field of the Invention
This invention relates generally to golf clubs and, in particular, to a type of golf club commonly referred to as "woods" which have an enlarged head attached to one end of an elongated shaft.
2. Description of the Prior Art
A full set of golf clubs generally consists of a correlated set of wood type clubs and a correlated set of iron type clubs. A conventional wood type golf club is disclosed in U.S. Pat. No. 3,625,518 while conventional iron type golf clubs are disclosed in U.S. Pat. No. 3,655,188. Wood type golf clubs have heads constructed of materials such as wood, metal and plastic. Iron type golf clubs have heads usually made of metal.
Referring to FIGS. 1-3, a wood type golf club according to the prior art has an enlarged head 10 including a specially shaped body 12 preferably formed of wood with a hosel 14 which receives and is attached to one end of an elongated shaft 16. A grip (not shown) is mounted on the other end of the shaft 16 so that head 10 may be swung in an arc to contact a golf ball resting on a tee or on the ground. An insert 18 preferably formed of a resin material is centrally mounted in a face portion 12a of the body 12, and a metallic sole plate 20 is attached to a bottom portion 12b of the body 12 by a plurality of screws 22 and/or epoxy. The sole plate 20 has an arcuate notch 24 at one end and a straight edge 26 at the other end. When the sole plate is attached to the body 12, the notch 24 and the edge 26 are engaged with an arcuate shoulder 28 and a straight shoulder 30, respectively, formed on the body 12. the sole plate 20 also has a curved side 32 and a relatively straight side 34. Shoulder 30 is located in a heel 10a of the head 10 while shoulder 28 is located in a toe 10b of the head 10.
When making a wood type golf club that is designated as a driver or a No. 1 wood, a hole 36 shown in FIG. 1 is bored in the bottom of the driver body 12 to remove weight therefrom so that the finished golf club will have a desired swingweight. Swingweight is generally defined as a measurement of a golf club's weight distribution about a point which is at a specified distance from the grip end of the golf club. Hole 36 is necessary because the body 12 in a driver is larger and heavier than in other golf clubs in a correlated set. When making other wood type golf clubs with relatively smaller heads (e.g., those designated as Nos. 3, 5 and 7 woods), holes 38, 40 shown in FIG. 2 are bored in the body 12 and then filled with weighted inserts 39, 41 made of lead or brass in order to provide finished golf clubs of desired swingweights. In a correlated set of wood type golf clubs according to the prior art including for example Nos. 1, 3, 5 and 7 woods, the sole plates 20 on the Nos. 3, 5 and 7 have been made of a heavyweight material such as brass whereas the sole plate 20 on the No. 1 wood has been made of a lightweight material such as aluminum. This helps to reduce, but not eliminate, the additional weight that must be added to the body 12 in the Nos. 3, 5 and 7 woods by using the weighted inserts 39, 41.
The golf club shown in FIGS. 1-3 has the face portion 12a of the body 12 arranged for contacting a golf ball. Located on the face portion 12a is a center point 11 known as a "sweet spot" which is in general alignment with the center of gravity of the head 10. If the head 10 impacts a golf ball at precisely the sweet spot 11 during a golf swing, maximum energy will be transferred from the head 10 and the golf ball will travel along its intended path. If the club head 10 impacts a golf ball at off-center points 11a, 11b which are also located on the face portion 12a but in the heel and toe 10a, 10b of the head 10, twisting movements of the head 10 will occur resulting in less than maximum energy being transferred from the head and deviation of the golf ball from its intended path of travel. Such deviation of the golf ball is generally referred to as a "slice" or a "fade" when impacting the head 10 at point 11a and as a "hook" or a "draw" when impacting the head 10 at point 11b.